In an image forming apparatus, such as a copier, a printer, or a facsimile machine, using an electrophotographic process, a latent image formed on a photoconductor is developed into a visible image with toner in a developing device. The toner is consumed through development of latent images, and it is necessary to replenish the developing device with toner. Therefore, a toner replenishing device, as a powder supply device, provided in the apparatus main-body conveys toner from a toner container, as a powder container, to the developing device in order to replenish the developing device with toner. With the developing device replenished with toner as described above, it is possible to continuously perform development. The toner container is detachably attached to the toner replenishing device. When the stored toner is used up, the toner container is replaced with a toner container containing new toner.
The toner replenishing device and the toner container of the image forming apparatus are shared among various models in order to reduce cost. PTL 1 describes a technology for providing a model-specific or color-specific identifier shape portion, which is a portion of a toner container formed in a different shape for a different type of the toner container.
The toner container described in PTL 1 has a cylindrical shape. When the toner container is set in the main body of the image forming apparatus, the toner container receives rotation drive from a main body of an image forming apparatus, and rotates about a center line, as a rotation axis, of the cylindrical shape to discharge toner from a discharge port. A unique identifier shape portion is provided on one of two bottom surfaces of the cylindrical shape, in particular, on an end surface on the downstream side in an insertion direction for insertion to the main body of the image forming apparatus (hereinafter, this end surface is referred to as a “front end surface”).